I run a Mendelmax 2.0 in my home office. Wife hates it because of --you guessed it-- the noise. I don't have time to build one but I did find a pretty decent off the shelf printer enclosure at the Home Depot.
I bought one of these
Gladiator cabinets from the Home Depot to contain the noise of my printer. It's much quieter now...
A lot of the homebrew cabinets use plexiglas for doors or walls so you can see the print in progress, but I put a webcam inside stuck to the side wall with a magnet to keep an eye on things. I will probably upgrade this by gluing in some plexiglas windows where the plastic handles are located on the sides. (can't see these handles in the photo but they're the same as the door handles only placed at upper front of each side). Haven't drilled a proper hole for running the wiring so I just have the wires temporarily snaking in from wherever I could find an opening.
Disregard the casters the unit comes with. I used a dozen rubber stoppers to support and sound-isolate the bottom surface. I've got some acoustic foam panels coming from Amazon to line the inside walls but frankly it is so quiet now I probably won't need them. This unit also comes with a central drawer that is easily removed along with the sliders.
I also don't have to worry about drafts messing up the print quality. With the doors closed the Gladiator box gets nice and toasty inside (somewhere around 40C) and this so far has made for more consistent prints.